Really glad it is severely curtailed in France.
Spain is out of control... last time I was there it was everywhere.
Greece seems to be getting worse... I go to the same places every year and I noticed more a few weeks ago.

I've never seen DCC offered at an ATM, now that I think of it - just at hotels and retailers. But then again, I generally try to steer clear of non-bank ATMs, as they tend to be sketchier. Is this something that banks will do to their own machines, or is it just the third-party vendors?

I was last in Spain a couple of times in 2018, but I didn't have this issue. Then again, I don't think I actually used a credit card more than twice at a restaurant or retailer, as I generally take cash out at the ATM and then pay for everything with that cash (just a personal trick I use to better control my spending). I know when I was in Iceland in late 2017 I bought a wool blanket at a tourist shop in Reykjavik, and the terminal there offered DCC, but the guy kindly recommended against it upfront.

This isn't exactly DCC, but one thing I have seen is hotels that quote you a rate and charge your credit card in USD, even if that isn't the country's local currency. I had this happen in Uruguay and Israel - the hotel would list its rate as USD60 or whatever, the charge slip would be in USD, and the transaction would hit my card in USD for the exact same amount. So there was nothing underhanded - they just had a parallel currency system for those transactions.

Now that I think of it, in 2019 I was in Israel, flying back from TLV, and stopped into a duty-free shop at the airport to buy some chocolates to take to my office the next day. They had two prices posted, one in shekels and one in USD, and (thinking this was a DCC issue), I specifically asked to be charged in shekels. Then when the transaction hit my CSP card and it was converted, it ended up costing me like 60 cents more than the posted price in USD :p

Multi currency conversion
This can also be a source of abuse - Airbnb (at least used to) forcing the multi currency conversion based on user locale and adding a 3% surcharge no matter what the property was listed for in local currency.

IME Switzerland is one of the worst offenders. They allow mandatory DCC in ATMs, train ticket booths, etc. Human agents just tell you have no option to pay in Swiss Francs with your card. My experiences were limited to canton Zurich, but left me deeply disgusted with the whole country.

Yes some bank ATM do offer DCC. CIBC ATMs in Canada do.

If they accept Amex, that would be my option to pay in Swiss Francs then.

Really?? I haven't been to Canada since last January, but I don't recall ever seeing a DCC option at an ATM there. But the last time I used a CIBC ATM would probably have been at least three years ago, so not sure if it might be a recent addition. My last trips have been to Quebec City, and I usually use a Desjardins ATM there, and DCC has never been offered.

CIBC ATMs been like that for at least a couple of years. Other bank (TD/ Desjardins/ National Bank / RBC) and even deli/gas station ATMs don’t DCC in Montreal.

If your card was issued in USA, payment terminals only displayed the amount in USD, and no other option was available. That's what I meant by mandatory DCC that got me fuming.

There's a CIBC branch at St.-Laurent and Prince-Arthur where I've used the ATM in the past, but I haven't been in Montreal since at least 2018, and I don't remember that issue. As someone who's lived in Canada and pre-pandemic would go up there at least once and usually multiple times per year, I've never come across DCC. Now I really want to try a CIBC ATM haha.

I thought Amex cards don’t allow DCC - mandated or optional. Is that no longer the case?

Never heard of it, but would love to know what made you think so.
If true, how would AmEx implement that -- reject charges in the card's own home currency?

read, for example, posts in this thread starting at around #320.

I am fairly certain that Amex used to not support DCC, and it was cited by many as a solution to avoid accidentally getting hit with this scam. Not 100% sure if that is still the case, and I don’t have time right now to read this thread backwards to see if there was definitely a change.

I don’t know, but since they own the network and the cards, perhaps their network simply doesn’t or didn’t allow transactions in any currency other than the currency of the merchant.

AMEX acceptance agreement (between AMEX and merchant) requires charges to be submitted and paid in local currency.

That's good to know. I'll test if this still applies next time I'm overseas. Lately I noticed that AmEx joined Visa and MC in being "creative" in their own FX conversion. For example, they quoted me one rate on a pending airfare purchase, slightly delayed settlement, and ultimately used a much worse rate. When I checked Oanda, I found that there was indeed a brief rate srike in the 3 days of interest, and AmEx used the absolute worst rate to charge me. In the past, AmEx claimed that FX conversions in customer accounts are not used for the bank's benefit. Under the new management I'm seeing it's no longer the case.